Arch Linux

alex_anthony

Member

From: UK

Registered: 2007-09-25

Posts: 344

[Solved] Possible broken partition table - any way to recover hard dri

I was doing some partition shuffling in advance of trying to upgrade my Windows 7 partition to Windows 10, but it died (it seemed to hang/be working for a while, then the whole machine turned off).

Now I think my partition table is broken or something.

Before things got screwed, I think I had an ext4 Arch partition, an NTFS Win7 partition, an extended partition with an Ubuntu partition and a swap partition, and a windows recovery partition kicking around.

GRUB starts but reports no such partition. I can load a live grub using super grub disk, which can read my arch grub menu entries and the one for chainloading to Windows 7.

If I try to boot my Arch partition from here, I get a kernel panic for out of memory.

If I try to boot my Windows partition, it just hangs at the Starting Windows screen. Same for trying to boot from a Windows 7 install usb. I'm guessing this is hanging on the equivalent stage.

Booting a modern gparted live usb gives out of memory errors, with it looping over killing udev. Errors to do with blkid.
If I boot with ahci blacklisted, I can get a (currently an older GParted) live CD to boot, but can't see the hard drive. If I then modprobe ahci, the whole system hangs, with cpu and memory maxed out. If I run top while it's doing it, it again looks like blkid. Before modprobing, fdisk and testdisk don't show the disk at all (obviously - no driver).

I've done a good few passes with memtest86+ and no errors.

I have almost everything backed up, except for one folder that wasn't in my dropbox (oops). So if possible I'd like to be able to fix the partition table enough to read the hard drive again. If that's not possible, I just need to be able to get to a state where I can access it enough to format it and start again.

The only idea I've come up with so far is fiddling with BIOS options and changing from ahci, but I have no idea if this would help at all/what else it might do. Or finding some live cd that won't choke on the partition table.

Partition table is MBR not GPT.

Any ideas?

For something that sounds vaguely similar, see here (didn't want to necro-bump):
https://bbs.archlinux.org/viewtopic.php?id=143604

Last edited by alex_anthony (2015-08-16 07:24:01)

mich41

Member

Registered: 2012-06-22

Posts: 796

Re: [Solved] Possible broken partition table - any way to recover hard dri

Oh, the beauty of automatic partition scanning. AFAIK there is no obvious way to disable it.

You may try this, maybe something like blkdevparts=sda:- will create one whole-disk partition and disable the scan. If this works, you would then need to run fdisk, cfdisk, gparted or something like that to see what's going on and try to fix it.

Alternatively, try non-Linux-based editors. A decent and very low-level partition editor which doesn't panic on messed disks is "Ranish Partition Manager", but it runs under DOS There are ways to setup a bootable DOS pendrive, another way is to get some bootable DOS floppy image, add ranish to it and then burn it to CD (or a real floppy, if your machine has FDD ).

I also remember some Windows-based bootable CDs filled with diagnostic software from the early 2000', maybe they still exist somewhere.

alex_anthony

Member

From: UK

Registered: 2007-09-25

Posts: 344

Re: [Solved] Possible broken partition table - any way to recover hard dri

Oh my god thank you!!

I went down the Ranish route.

If anyone is interested, I used a mixture of these two to get a live USB for it:
http://humpty.firstcloudit.com/blogs/ra … h-usb.html
http://www.howtogeek.com/136987/how-to- … usb-drive/

Telling Ranish to look at that hard drive gives an error "MBR/EMBR partition overlaps an existing partition. Partition not imported"

I remembered what I'd been doing when things broke wasn't fiddling with the partitions per se, rather changing which was the active boot partition. So i toggled that, saved it in RPM.

GRUB still wouldn't load, but I gave it a whirl booting from the Windows 7 install USB I'd made (because it was still kicking around) and bam it actually loaded.

Ditched that, made a super grub disk usb again, loaded that, and booted successfully into my Arch partition woop woop. All seems to be working fine, except my Ubuntu partition (which may have been running grub, if thats what i installed last) is missing - but I don't care about that one.

Thank you so much!